MicroRNA-8 is a Regulator of Cuticle Pigmentation in Drosophila Melanogaster

Iryna Shakhmantsir, Vassar College '12 and Prof. Jennifer Kennell

MicroRNAs are short non-coding RNAs that post-transcriptionally regulate gene expression by binding to 3' UTRs of their target mRNAs. Our research focuses on studying the function of the microRNA miR-8 in Drosophila melanogaster. Previous studies have identified miR-8 as a regulator of Wnt and insulin signaling, neurodegeneration and neuromuscular junctions. We have found that miR-8 can also regulate cuticle pigmentation in Drosophila. Female miR-8 mutants are characterized by lighter pigmentation than wild- type flies. A previous student in the lab identified two potential miR-8 targets associated with cuticle pigmentation, Bab1 and Bab2. Reporter gene assays in cell culture suggest that these genes are downregulated by miR-8 in vitro. We have extended the previous findings to show that miR-8 can inhibit Bab2 expression in vivo in the developing wing. Additionally, four putative miR-8 targets, all belonging to the family of cuticular proteins (cpr), have been tested in cell culture using reporter gene assays. We have found that miR-8 can inhibit Cpr56F and Cpr49Ag in vitro. Our studies suggest that miR-8 can potentially regulate multiple genes in the cuticle pigmentation pathway of Drosophila melanogaster.